() A House task force on declassifying secrets held its first hearing on the JFK files on Tuesday afternoon.

Filmmaker Oliver Stone, a proponent of conspiracy theories on the subject, was a witness along with authors Jefferson Morley and James DiEugenio.

Task Force Chair Rep. Anna Paulina Luna, R-Fla., opened the hearing by asking people to keep an open mind.

“Let me be clear: There are sincere concerns and discrepancies regarding the Warren Commission pushing forward a narrative without all the facts and according to testimony of various witnesses, omitting evidence,” she said.

The witnesses tread familiar ground in the hearing, discussing what they say are discrepancies in government accounts of the assassination and calling it unacceptable to have files still unreleased so many years later.

President Donald Trump promised to declassify files on the assassinations of President John F. Kennedy, candidate Robert F. Kennedy and civil rights leader Martin Luther King Jr. as well as accused sex trafficker Jeffrey Epstein.

Tens of thousands of files on JFK were released in March, but there does not appear to have been any groundbreaking new information. Because the files were released in such a way that it was difficult to tell which had been released before and which had new information, historians and experts have said it will take significant time to go through them.

The released files were only those held by the National Archives. Files held by other agencies, including the FBI and CIA, were not released.

Regarding the files, Morely said they showed the CIA had far more information on assassin Lee Harvey Oswald than previously known. That could raise the question of whether the agency could have done more to prevent the assassination.

Oswald has been at the center of conspiracies, with suggestions that he was not the only shooter or was set up as a patsy and that his assassination by Jack Ruby was part of a cover-up.

The declassification task force had previously said it would hold hearings on the JFK files, at one point saying it would call those involved in Kennedy’s autopsy to testify, which would be difficult since all of them are dead.

“After six decades of deception and secrecy surrounding the assassination of President Kennedy, the Trump Administration is lifting the veil and giving the American people the truth. By investigating the newly released JFK files, consulting experts, and tracking down surviving staff of various investigative committees, our task force will get to the bottom of this mystery and share our findings with the American people. Our hearing is the first step and we look forward to hearing from our witnesses,” said Luna.